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Microsoft Build Engine Started by a Script Process

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Microsoft Build Engine Started by a Script Process

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An instance of MSBuild, the Microsoft Build Engine, was started by a script or the Windows command interpreter. This behavior is unusual and is sometimes used by malicious payloads.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*

Severity: low

Risk score: 21

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 13 (version history)

Added (Elastic Stack release): 7.7.0

Last modified (Elastic Stack release): 8.4.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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The Build Engine is commonly used by Windows developers but use by non-engineers is unusual.

Investigation guide

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Rule query

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process where event.type == "start" and (process.name :
"MSBuild.exe" or process.pe.original_file_name == "MSBuild.exe") and
process.parent.name : ("cmd.exe", "powershell.exe", "pwsh.exe",
"powershell_ise.exe", "cscript.exe", "wscript.exe", "mshta.exe")

Threat mapping

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Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Trusted Developer Utilities Proxy Execution
- ID: T1127
- Reference URL: https://attack.mitre.org/techniques/T1127/
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/

Rule version history

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Version 13 (8.4.0 release)

Formatting only

Version 11 (8.2.0 release)

Formatting only

Version 10 (7.16.0 release)

Updated query, changed from:

process where event.type == "start" and (process.name :
"MSBuild.exe" or process.pe.original_file_name == "MSBuild.exe") and
process.parent.name : ("cmd.exe", "powershell.exe", "cscript.exe",
"wscript.exe", "mshta.exe")

Version 8 (7.13.0 release)

Updated query, changed from:

event.category:process and event.type: start and
process.name:MSBuild.exe and process.parent.name:(cmd.exe or
powershell.exe or cscript.exe or wscript.exe)

Version 7 (7.12.0 release)

Formatting only

Version 6 (7.11.2 release)

Formatting only

Version 5 (7.11.0 release)

Formatting only

Version 4 (7.10.0 release)

Formatting only

Version 3 (7.9.1 release)

Formatting only

Version 2 (7.9.0 release)

Updated query, changed from:

process.name:MSBuild.exe and process.parent.name:(cmd.exe or
powershell.exe or cscript.exe or wscript.exe) and
event.action:"Process Create (rule: ProcessCreate)"

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